1) Field of the Invention
The present invention relates to a method for manufacturing a pattern sheet for plate-making useful for manufacturing a stamp or the like, and more particularly to a method for manufacturing a pattern sheet for plate-making capable of easily forming a positive image through the use of a photographic negative film.
2) Description of the Related Art
So far, various printers such as a stamp have been used for printing a desired printing image such as a picture and a character on a print medium such as a post card. The Japanese Patent Publication No. 7-115532 discloses a stamp manufacturing method utilizing a portrait (person image) or the like. In such a stamp manufacturing method, a desired image such as a portrait is read out through a scanner or the like to produce a mesh spot photograph expressed by printing the densities of a photographic image in accordance with the sizes of mesh spots. Subsequently, a portrait partial photograph is formed by cutting out a display section such as a portrait from an image of the mesh spot photograph and a background partial photograph is made after cutting out the display section.
In addition, the portrait partial photograph is put on a transparent film and is printed on a positive film, thereby forming a portrait mesh positive film. On the other hand, the background partial photograph is put on a transparent film and the transparent film is placed upside down and is printed on a negative film, thereby producing a background image film in which the cut-out section (the section from which the portrait is cut out) in the background partial photograph is true black. Thereafter, the portrait mesh positive film is pilled up on a photosensitive resin plate and exposed to light to produce a portrait resin plate, and further, the background film is placed upside down and is placed on another photosensitive resin plate and exposed to light to form a background resin plate.
In the case of such a stamp manufacturing method, the portrait resin plate and the background resin plate are used as pattern sheet for plate-making, and they are uniformly heated and are alternately brought into contact with the surface of a foamed resin plate, thereby manufacturing a stamp.
Furthermore, a method disclosed in Japanese Patent Application Laid-Open Nos. 8-118771 and 8-207409 can also manufacture a stamp through the use of an image such as a portrait. A pattern sheet for plate-making used in this stamp manufacturing method is expressed according to the densities of the desired portrait on the basis of the differences between the dot concentrations in a manner that a photograph including a desired portrait is copied onto paper, a film or the like, through which an infrared ray passes, by means of a PPC copying machine. In addition, the densities of the portrait based upon the dot concentration differences are expressed with a recording material such as an ink or a toner which absorbs or intercepts infrared rays.
However, in the case of the former of the above-mentioned prior stamp manufacturing methods, a problem arises in that there is a need to produce two kinds of pattern sheets for plate-making: one being the portrait resin plate made through the use of the portrait mesh positive film and the other being the background resin plate made through the use of the background film. In addition, for manufacturing a stamp, it is necessary to use two kinds of these pattern sheets for plate-making, and therefore, a plurality of steps are required for producing the pattern sheets for plate-making and for manufacturing the stamp, with the result that the stamp manufacturing method becomes complicated.
Moreover, because of manufacturing the stamp by alternately bringing the portrait resin plate and the background resin plate into contact with the surface of the foamed resin plate, the stamp surface corresponding to the portrait section and the stamp surface corresponding to the background section are overlapped with each other on the surface of the foamed resin plate, which causes the printed images made at the stamp sealing to become indistinct.
On the other hand, in the case of the latter of the above-mentioned prior stamp manufacturing methods, the pattern sheet for plate-making is formed through the use of the PPC copying machine. However, the PPC copying machine has not been popularized into average homes yet, and hence, they have to use a PPC copying machine installed in companies, schools, convenience stores or the like on all such occasions. In addition, since the pattern sheet for plate-making is produced by PPC-copying a photograph or the like, there is a possibility of the deterioration of the image quality of the pattern sheet for plate-making and the print image quality of the plate-made stamp.